CHANGES IN CEREBELLAR AND HIPPOCAMPAL SUPEROXIDE DISMUTASE (SOD) ACTIVITY IN RATS X-IRRADIATED AT BIRTH

CÁCERES, L.G.; GUELMAN, L.R

Buenos Aires, Argentina

Congreso; Reunión Anual de la Sociedad Argentina de Farmacología Experimental; 2007

Sociedad Argentina de Farmacología Experimental (SAFE)

CHANGES IN CEREBELLAR AND HIPPOCAMPAL SUPEROXIDE DISMUTASE (SOD) ACTIVITY IN RATS X-IRRADIATED AT BIRTH. Cáceres, L.G. and Guelman, L.R. 1ª Cátedra de Farmacología, Facultad de Medicina, UBA y CONICET. Paraguay 2155 – piso 15 – (1121) Buenos Aires. Email: lguelman@fmed.uba.ar Developing Central Nervous System (CNS) is highly sensitive to radiation-induced oxidative damage. With the aim to evaluate if this radiosensitivity is related to an alteration in the endogenous antioxidant system, the levels of SOD were determined in cerebellum (CE) and hippocampus (Hip) of 30 and 90-days old Wistar rats X-irradiated at birth with 5 Gy. Hippocampal SOD levels significatively decreased at 30 days post-irradiation (C: 0.37 ± 0.010 U/mg, Rx: 0.33 ± 0.009 U/mg de tejido, p< 0.05) and returned to control at 90 days. In contrast, cerebellar SOD activity remained unchanged at 30 days and significatively increased at 90 days post-irradiation (C: 0.41 ± 0.015 U/mg, Rx: 0.48 ± 0.009 U/mg, p< 0.05). These results suggest that hippocampal SOD seems to be more radiosensitive than cerebellar SOD at short term (30 days), probably due to radiation-induced reactive oxygen species (ROS) inactivation. Conversely, the increased levels of cerebellar SOD observed at long term (90 days) suggest the existence of a compensatory mechanism capable of counteracting excessive oxidative damage. These specific changes could reflect a differential regional radiosensitivity through the use of divergent adaptative mechanisms of the endogenous antioxidant system.